The Pros and Cons of Saliva (Oral) Drug Tests

When drugs are ingested by a drug user, they are broken down by the body into metabolites or by-products. These by-products are found in body fluids such as blood and saliva. In the saliva, the drugs themselves can be detected especially those taken orally. Oral drug tests consist of collecting a sample of saliva from the individual to be screened and subjecting it to tests which try to detect the presence or absence of drugs and/or their metabolites.

This method is simple and has other advantages but it also has its disadvantages.

Advantages of Oral Drug Tests

Non-Invasive: Saliva collection is easy and does not inconvenience the donor. There is no pain or discomfiture.

Easy Sample Collection: All the person has to do is provide saliva in a clean cup or the sample can be taken from the mouth using a clean swab.

Instant Results: Oral drug tests can be done as soon as the sample is given and the results can be obtained and analyzed without delay.

Checks Sample Adulteration: Sample collection can be done under supervision. The person being screened can provide the saliva right in front of the tester.

Inexpensive: The equipment used to carry out saliva drug tests is cheap and the tests are usually not required to be carried out in a laboratory.

Can Detect Very Recent Drug Use: Oral drug tests can be used to detect drugs which have been ingested very recently. This is advantageous over other tests like blood and urine tests which require the metabolites of the drugs to appear in the blood or urine and which may take a number of days.

Disadvantages of Oral Drug Tests

Limited Window of Detection: Drugs or their metabolites do not persist in saliva for more than a few hours. They are usually completely eliminated in about 24 hours. So for drug use to be detected the test must be carried out at a time not long after the person ingested the drug.

Cannot Detect Chronic Use: As mentioned above, drugs do not persist in saliva and ergo, saliva tests cannot be used to determine whether a person is a habitual drug user.

Possibility of Oral Contamination: Eaten food and the ingestion of otherwise legal products or drugs may affect drug results. An example is the ingestion of cough medication that contains codeine which is an opiate just like heroin or morphine. Tests for opiates or their metabolites can detect codeine which can be misinterpreted as illicit drug use.

Difficulty in Testing for Some Drugs: Some drugs or their metabolites hardly appear in saliva and therefore, may not be detected using oral tests.

Amount of Sample Provided: Some drugs can cause dryness of the mouth and thus, reduced saliva production. The person being tested may then not be able to provide adequate amounts of the sample for the test to be properly carried out.

Low Concentration of Compounds Tested For: The drugs which appear in saliva are usually found in low concentrations. Some times they may be too low to give conclusive results during testing. Commercial adulterants and mouth-washes can also affect the concentrations of the drugs being tested for.